Colloq Abstract - Hindson

by Hubertus Intema last modified Oct 06, 2017 by Lori Appel

Oct 13

11:00am Mountain

 

Luke Hindson (Hertfordshire)

 

The Resolved Radio Continuum vs. Star Formation Rate in Nearby Dwarf Galaxies

 

Abstract

The radio continuum (RC) emission associated with star forming galaxies (excluding active galactic nuclei) is directly linked to massive (>8 msun) stars and can therefore be used to trace star formation (SF) and gives rise to the RC-SFR relation. We have undertaken a study focused on the non-thermal component which dominates the RC component of the relation particularly at low frequency. The non-thermal emission is dependent on a complex interplay of physical processes such as the injection energy spectrum of the cosmic ray electrons, the magnetic field strength, and the cosmic ray energy density, and their mutual interaction. In this presentation we will show the results of VLA C-band (6 GHz)  observations of a sample of nearby dwarf galaxies taken from the LITTLE THINGS survey. By combining our VLA observations with ancillary data including H-alpha, 24um, and the FUV we separate the radio continuum emission into its thermal and non-thermal components and compare these to the SFR. We use these results to calibrate the RC-SFR relation on scales from 200 to 700 pc, explore the equipartition magnetic field properties of the galaxies, and the intrinsic scatter in the non-thermal RC-SFR relation. A properly calibrated and well-understood RC–SFR relation would allow for an extinction free estimate of the SFR in galaxies in the Local Universe and at high redshift making it an attractive probe of the SFR in galaxies at high redshift with upcoming surveys with the VLA and SKA precursors.